No low end power...any ideas?

[griffgj]

Hey guys! I've searched this magnificent forum over for ideas on why my 6.0L is like a slow boat to China but haven't found anything. Can anyone help me?

The problem:
From a dead stop, I floor it, it slowly starts to move, after several seconds, it has enough RPM to spool up the turbo, then starts to take off (set you back in the seat). In other words, when I floor it, I would expect it to put me back in the seat immediately (like all other diesels I've been in), but instead, the truck says "whoa, you want to go now? Well, gimme a little bit to work on it." Once the turbo has spooled up, it has "power" but you can tell it's still lacking.

Here's the specs:
- Bone stock 2006 F-350 6.0L automatic
- 85,000 miles

Here's the diagnostics:
- Fuel pressure: idle @ 70psi, WOT @ 65psi
- Boost: once spooled up, gets to ~25psi
- No trouble codes
- Just installed fuel pressure gauge and took off intake air tube going into the engine (post turbo/intercooler) and found a fairly substantial film of oil.
- Does not blow white/blue smoke out exhaust
- Fuel filters changed recently
- Cranks fine (hot or cold)

I've taken this thing to two different dealers, both telling me there's something going on, but they can't find it. One of them said there was some evidence of the injectors skipping, so they replaced 3 of them and the fan clutch. The other said the fuel tank was delaminating and replaced it. Neither of those "fixes" helped.

I hope I'm not abusing the forum, I'm just at my wits end trying to figure out why this thing acts so pathetic. If I've left anything out, please ask. Any and all help is greatly appreciated!

[Tuscany]

That's called turbo lag. Nature of the beast man if you can't live with it do a boosted launch by holding the break while you give it fuel to spool the turbo up to 5-10 psi then let out of the brake and stand on the skinny pedal. If you still don't like it than go back to gassers. (<-- Not meant to mean any disrespect)

[griffgj]

Well, I would agree with you, but I may not have exaggerated the problem enough. I have a buddy with a stock '03 6.0L and my father has a duramax, both of them say there is a definite problem with my truck. In their trucks, the lag is only but a second or two, in mine, it's like 6 or more seconds (timing may not be accurate, but you get the idea).

In addition to the extended lag though, it still does not "seem" to have the power my buddy's truck has. I know this is subjective, but even the diesel mechanics at the dealership recognize the problem, they just don't know what to do about it. I was just hoping someone on here might have enough experience with these things to give me some things to try that my local dealership is too lazy to do.

[Tuscany]

Do you have a monitor in the truck? E.g; Dashboss, Edge Insight CS/CTS, Scangauge II, AutoEnginuity?

[griffgj]

Nope. Just stock gauges and fuel pressure gauge. I do have a bluetooth scan tool and Torque app for my phone, but not sure what I need to monitor. Does that count?

[Tuscany]

Yes it is a start. Monitor the VGT duty cycle % as well as FICM voltage and ICP pressure and IPR %.

[southend]

Originally Posted by Tuscany

Yes it is a start. Monitor the VGT duty cycle % as well as FICM voltage and ICP pressure and IPR %.

Also battery voltage, and boost. Check for torn/busted cac boots, exhaust leaks, and the presence of soot around the engine compartment.

Sent from my phone that somebody didn't help me get.

[griffgj]

Thanks for the suggestions! Here's what I found:

@ idle (~580 RPM)
- Battery: 13.3V
- FICM: 48.5V
- ICP: 588psi
- IPR %: 21.6%
- VGT duty cycle: 75%
- Boost: .14psi

@ WOT (~3900 RPM)
- Battery: 13.3V
- FICM: 47V
- ICP: 3937psi
- IPR %: 76.9%
- VGT duty cycle: 38%
- Boost: 22.7psi

I have an excel file of all the numbers, if you wanted to see it. How do these numbers look? Anything else I need to look for? Thanks again!

[portcity_gt]

Your buddies 03 is faster, because the 03's were touched by the hand of god lol.
But seriously the 03 has a different turbo so it's caritureistics will be different, but I'm thinking the 10 vein has more lag, I could be remembering Wong tho.

[Tuscany]

Those numbers look good mate.